This study is testing the hypothesis that production of active vitamin D metabolites in human granuloma-forming disease like sarcoidosis is not subject to regulation by those physiological factors which normally control the renal synthesis of 1,25-(OH)2D. Instead, it is thought that hormone production by macrophages in these disease states is regulated by locally produced or circulating immunomodulatory agents and in an intracrine/autocrine fashion by endogenously synthesized nitrous oxide and a vitamin D stimulatory factor. Bronchoalveolar lavage specimens are collected from patients undergoing bronchoscopy at both CSMC and USC. Seven specimens were collected in 1996 but efforts are continuing to improve this acquisition rate by establishing closer relationships with the staff of the bronchoscopy laboratories.